This Pentax SMC DA lens is designed to work specifically with digital SLR cameras. Equipped with a focal length equivalent to 60 mm in 35 mm format, the 40 mm f/2.8 lens is ultra compact because of the pancake-style design, and light with a weight of only 3.2 oz. This Pentax lens is treated with Super Protect (SP) coating for maximum light transmission, sharp definition, and high-contrast images. The advanced optical design used on the Pentax SMC DA lens provides high-resolution optics with minimal aberrations while the Quick Shift Focus System allows for instant toggling between autofocus and manual focus modes. With this 40 mm f/2.8 lens, users can take advantage of the 39-degree angle of view and minimum focus distance of 15.7 inches, as well as a 49 mm filter size. The maximum reproduction ratio for the Pentax lens is 1:7.69 and the lens has nine diaphragm blades. The size of the Pentax lens is approximately 2.5 inches by 0.6 inches, making it very easy to carry attached to a camera or in a camera bag.